Packaging of breakfast cereal is customarily effected by sealing the dry cereal product within a plastic bag and storing the filled bag within a suitably sized cardboard box or carton. A disadvantage with this type of packaging is that once the sealed bag is opened, it is difficult to reseal the bag in an airtight manner necessary to maintain freshness of the cereal product.
In order to close a conventional cereal bag after the sealed top end has been opened, the user will typically fold the opened end of the bag over onto it self one or more times. Closing the bag in this way is awkward. Oftentimes, the user will simply stuff the opened end of the bag down into the box without regard to properly sealing the opening. Once opened, the conventional cereal bag is never again airtight. In humid climates, in particular, exposure of the dry cereal product to air quickly compromises the freshness of the cereal product. Furthermore, as additional serving portions of the cereal product are emptied from the bag with each use, it becomes more difficult to effectively seal close the open end of the bag by rolling the bag within the depth of the box or carton.
Another problem with conventional cereal bags is that it is difficult to open the sealed top end of the bag without also ripping or tearing the side panel walls of the bag. An unevenly opened bag often has an overhanging portion that blocks or traps cereal during pouring. In the case where the bag is used as a liner within a box, the overhanging portion of the ripped open bag often also causes spillage of the cereal contents into the crevice space between the bag and the box as the box is returned to the upright position. A flexible bag formed with an easily openable reclosable pour spout that overcomes the above-noted problems of the prior art would be desirable.
Flexible plastic bags or cereal box liners having a reclosable fastener or zipper for packaging cereal are known from the prior art. Examples of prior art flexible plastic bags having a reclosable fastener are found in U.S. Pat. Nos. 4,759,642, 4,946,289, and 5,080,253. In each of the bags disclosed is these patent documents, the reclosable fastener extends transversely across the entire width of the bag. None of these patent documents disclose or teach a bag having a reclosable fastener or associated structure that is configured to form a natural pour spout when the zipper material is opened. Quaker Oats currently markets a cereal bag having a zipper-type reclosable fastener under the trademark ZIP PAK. Like the prior art noted above, the reclosable fastener of the ZIP PAK bag extends across the entire width of the bag. The ZIP PAK bags, like most cereal bags on the market these days, are mass produced from a single web of film material using conventional in-line vertical form, fill and seal (VFFS) packaging equipment. As a result of the VFFS production process, the overlying front and rear panel walls of the bag are joined together by a joining fin seal that runs the longitudinal length of the bag. In the ZIP PAK bags, in particular, the joining fin seal bisects the zipper-type reclosable fastener across the top of the bag. Thus, there is a tendency for the joining fin seal to obstruct zipper closure action as the user applies thumb and finger pressure in a sweeping motion across the length of the zipper-type reclosable fastener. This obstruction often results in the bag not being completely sealed. Difficulty in airtight resealing a bag with such "full width" zip closures is compounded in the case where the bag is also used as a box liner.
U.S. Pat. Nos. 4,953,708 and 5,060,803 disclose flexible bags that form pour spouts when opened. The bags in these patent documents lack any resealable structure for the pour spouts and they require the sides of the bag to be gussetted which increases the cost of manufacture.
U.S. Pat. No. 4,332,344 discloses a flexible package for enclosing liquid or granular products which includes a tubular plastic bag and a pleated reclosable pour spout that is appended to the side edge of the bag. A bag of this configuration is complex in design and would be extremely expensive and difficult to mass manufacture using conventional VFFS equipment.
U.S. Pat. No. 5,611,626 discloses a bag with a corner tear-away pour spout opening. This patent teaches to reseal the bag after each use by attaching a separate adhesive patch to cover the corner pour spout opening. A drawback with this resealing approach is that the glue on the adhesive patch tends to loose its effectiveness after repeated uses. Also, since the adhesive patch is separable from the bag, it may become lost through carelessness of the user, thereby leaving the user without a convenient means for resealing the bag.
Accordingly, a bag having a pour spout which includes integral structure or means for resealing the pour spout and which is also easily mass produced using conventional VFFS equipment would constitute a significant advance in the art.